Portable audio devices have become extremely popular devices in recent years. Their popularity has soared, in part, as a result of a reduction in electric component power consumption, which makes long battery life possible, and a reduction in cost of digital data storage, which makes carrying large collections of music in a pocket-sized device possible. Further, mobile phones and tablets function as portable audio devices, and mobile phone and tablet ownership has significantly increased as a result in declining prices of smartphones and tablets, and increased availability of 4G technology that allows streaming and downloading of audio files to the smartphones and tablets. Although audio quality from portable audio devices has increased over the time of growth of the portable audio device market, audio quality has generally not been a primary differentiator between devices. However, as other technological improvements, such as storage density and power consumption, are coming at a slower rate, consumers are beginning to evaluate devices based on audio quality. Further, professional and semi-professional musicians and technicians are making more use of portable audio devices in their businesses, which also demand high audio quality.
One popular manner of consuming audio from a portable audio device is headphones. Headphones vary in cost, such as from a few dollars to a few thousand dollars, and the quality of the headphones span a similarly wide divide. The varying characteristics of headphones on the market can cause a portable audio device to sound significantly different depending on what headphones are plugged into the device. Conventional portable audio devices, such as a smartphone 102 of FIG. 1, detect when a set of headphones is attached. The device uses this indication to determine when to turn off the loudspeaker. However, conventional portable audio devices generally have no other information about what is plugged in to the headphone jack. For example, one set of headphones 104A may have a DC load impedance of 12 ohms, whereas another set of headphones 104B may have a DC load impedance of 50 ohms. The DC load impedance, one characteristic of the headphones 104A and 104B, can affect the sound quality and sound intensity generated by the smartphone 102. However, because the smartphone 102 has no information about such characteristics, the smartphone 102 is unable to compensate for the difference between headphones 104A and 104B.
Shortcomings mentioned here are only representative and are included simply to highlight that a need exists for improved electrical components, particularly for audio devices employed in consumer-level devices, such as mobile phones. Embodiments described herein address certain shortcomings but not necessarily each and every one described here or known in the art.